Perfusion catheters used for introducing or removing fluids from a body lumen are well known in the art. Such catheters may be used in drug therapy, such as chemotherapy, where the fluid to be introduced is a pharmaceutical agent. Perfusion catheters have also been used to allow for bypassing occlusions in blood vessels. For example, during angioplasty, plaque may become partially or completely dislodged and may form a restriction that at least partially occludes an arterial passage. A perfusion catheter may be positioned in the occluded blood vessel across the restriction, such as is described in U.S. Pat. No. 4,661,094, incorporated herein by reference, to allow blood to flow into the catheter through a first opening upstream of the restriction and flow out through a second opening downstream of the restriction. As described in the '094 patent, the openings may be distributed in a helical pattern in the sidewalls of the catheter.
During the intake of fluids, however, the sidewall hole orientation may have certain disadvantages. For example, the holes may contact and seal against the walls of the duct or vessel in which the catheter resides, thereby blocking the holes and minimizing flow. One typical use for perfusion catheters for fluid intake is in extracorporeal blood purification procedures, such as hemodialysis. Modern procedures favor the use of dual-lumen catheters such as those described in U.S. Pat. No. 4,134,402, incorporated herein by reference, or other multi-lumen catheters, such as those described in U.S. Pat. No. 4,995,865, incorporated herein by reference. In a standard dialysis procedure using a dual- or multi-lumen catheter, blood is withdrawn from a blood vessel in a patient through one or more lumens of the multi-lumen catheter and supplied to a hemodialysis unit that purifies the blood. The purified blood is then returned to the patient through another lumen of the catheter.
The '865 patent describes multi-lumen catheters having side openings located on “spiral pathways.” The ranges of these spiral pathways, however, are limited to the portions of spirals contained within two pie-shaped intake lumens that each comprise only a 90° quadrant of the circular lumen. Thus, if there is a tendency for one circumferential portion of the catheter to be blocked and that portion happens to fall within one or both of the quadrants comprising the two intake lumens, the spiral configuration is insufficient to keep the flow into the openings from becoming occluded. Occlusion of intake holes may reduce the intake flow significantly enough to lengthen the amount of time a patient may have to undergo the hemodialysis procedure, causing unnecessary discomfort for the patient, and causing inefficient use of resources for the dialysis provider.
Therefore, there is still a need in the art for a catheter structure that resists occlusion of openings in the sidewall.